In a turbo refrigerator which is provided with a turbo compressor which is driven by a motor, for example, the cooling of the motor is performed by supplying some of a refrigerant which circulates between an evaporator and a condenser to the motor (refer to, for example, Patent Document 1). Furthermore, in a turbo refrigerator as disclosed in Patent Document 1, usually, lubricating oil is always supplied to a gear or the like which connects a rotating shaft of a motor and an impeller, and the lubricating oil is cooled by a heat exchange with the refrigerant and then supplied to the gear or the like, thereby cooling the gear or the like.
Patent Document 2 discloses a technique of integrating an intermediate cooler which is provided between a condenser and an evaporator and supplies some of a refrigerant liquefied in the condenser to a turbo compressor, with a motor for the driving of the turbo compressor.
Patent Document 3 discloses a pressure equalizer which connects an oil tank storing lubricating oil and a compression mechanism which is a space in which an intake capacity control section (an inlet guide vane) for controlling the capacity of a refrigerant passing through a turbo compressor, and a low-stage compression section and a high-stage compression section of the turbo compressor are installed.